1. Scope of the Invention
The invention pertains to any arrangement of fluid circuits which includes flexible hoses that require connections, branch-hoses or bleeding devices and, especially, to thermal exchange circuits mounted on automobile or road vehicles.
Said fluid circuits are designed for linking different parts--or engine units in the case of vehicles--and they must display, simultaneously, longevity features,--in spite of the hostile environment resulting from temperature, pressure, the presence of greases or oil-chemical resistance to conveyed fluids and airtightness.
The linking of different engine parts or units implies that the flexible hoses include a number of connections, most often on rigid nozzles, usually metallic, as well as branch-hoses of which the diameters can be equal to that of the main hose or different therefrom.
Whereas the flexible hoses display a high degree of reliability because of the character of the constituent elastomer material(s) which include(s) usually reinforcement elements, continuous or discontinuous, comprised of textile or metallic substances, the connecting zones with parts or units and those for connecting the branch-hoses or bleeding devices on the main hosing represent weak points where leaks can occur or even disconnections triggered by tear-off under the effect of pressure and temperature or simply because of the creep of elastomer-based compounds under these hostile circumstances.
2. Description of the prior art
In order to alleviate these risks, various solutions have been offered. Some, which are purely mechanical, like those described in patents EP 88 571 or DE 3 430 053, pertain to inserting inside the flexible hose a rigid pipe, which is usually metallic, fixed with any means and having an enlarged end.
Other solutions attempt to prevent the risks of probable leaks or disconnection with a rubber- or synthetic resin-based duplicate moulding, as suggested in patents FR 2 506 892, FR 2 562 886 or EP 0 110 102.
The current solutions display many inconveniences:
they weaken the intrinsic resistance of the main flexible hose, by requiring the boring of the wall that reduces the section of materials which will be subjected to mechanical stress or destroys, locally, the reinforcement of said wall; furthermore, this boring induces, along the crests of the bored hole thus performed, incipient tearing in a zone that, during operation, will be highly stressed;
their manufacturing is difficult because they require the introduction, inside the main flexible hose, either of metallic anchoring parts in the case of mechanical solutions, or, for the duplicate moulding solutions, inner cores inside the branching zone, in order to ensure vital counterpressure during the duplicate moulding operation, followed by their extraction once the operation is over. In order to facilitate those manipulations, the inner cores are often coated with a lubricating, anti-adhesive agent from rubber, that can contaminate the duplicate moulding zone and thus hamper the quality of the intimate linking that is necessary between the duplicate moulding and the outer surface of the flexible hose. Moreover, the inner core introduction and extraction operations might trigger, on the inner side of the main and secondary flexible hose, wounds which, although superficial, produce incipient constraints that accelerate the decay of said hoses;
their manufacture is costly, in terms or laying the metallic inserts inside the flexible hose in the case of mechanical solutions, and of requiring two successive operations,--injecting the duplicate moulding material onto the flexible hose then vulcanizing under pressure, inside the mould which lasts for several minutes and subsequently mobilizes implements, in the second category of solutions;
they prohibit the laying of branch-hoses of the same diameter as that of the main flexible hose, because of the size required for passage of the metallic insert or of the inner core; they also prohibit, for reasons of difficult access, the laying of branch-hoses inside zones far away from the end of the main flexible hose;
in the case of duplicate moulding, they shorten the life span of the main hose by requiring additional thermal treatment of the branching zone which leads to overvulcanizing the rubber-based mixture, therefore to a weakening of mechanical features and to a less resistance to ageing, in the considered zones.
finally, they require a state of perfect cleanliness in the areas to be assembled and they therefore require the use of solvents for reviving them, which is noxious to health at the work station and produces risks of fire or explosion in the shop.
Analysis of the prior art obviously indicates that a device which enables connections, branching of hoses or bleed to be made on a flexible hose, which displays the necessary reliability features while being economical from the manufacturing standpoint, is not known.
Moreover, we must note that the evolution of industrial technology--that of automobiles, especially--increases substantially the operating constraints, more specifically, in the areas of temperature and pressure.